针刺抑制直结肠伤害性扩张引起的大鼠脊髓背角神经元反应

目的:探讨针灸缓解内脏痛的机制.方法:选用SD大鼠,采用直结肠扩张(CRD)作为内脏的伤害性刺激.微电极细胞外记录L1～L3节段脊髓背角广动力型神经元活动.针刺选用与直结肠同神经节段支配的同侧和对侧"足三里"穴位.结果:内脏伤害性传入能明显激活脊髓背角会聚神经元,对侧体表机械刺激和"足三里"穴位手针刺激可抑制这种伤害性反应.急性脊髓化实验,针刺对侧"足三里"穴位抑制CRD反应的效应完全消失.结论:针刺和内脏伤害性传入信号在脊髓水平发生会聚和相互作用,针刺穴位能够抑制内脏伤害性传入所激活的背角神经元反应,且这种作用需要脊髓上中枢参与.

Acupuncture inhibiting responses of spinal dorsal horn neurons induced by noxious dilation of rectum and colon

OBJECTIVE: To study on mechanisms of acupuncture in relieving visceral pain. METHODS: In SD rats CRD was used as noxious visceral stimuli. Activities of spinal dorsal horn wide dynamic (WDR) neurons of L1-L13 were recorded by extracellular microelectrode technique. Acupuncture was given at ipsi-lateral and contra-lateral Zusanli (ST 36) of the same segmental innervation of rectum and colon. RESULTS: Visceral noxious afferent could significantly activate spinal dorsal horn convergent neurons, and mechanical stimulation of contra-lateral body surface and hand acupuncture at Zusanli (ST 36) could inhibit this noxious response. When the spinal cord was acutely blocked, the inhibiting CRD effect of needling CRD effect of needling contra-lateral Zusanli (ST 36) completely disappeared. CONCLUSION: Acupuncture and visceral noxious afferent signals converge and interact each other in spinal level, and acupuncture at acupoint can inhibit the spinal dorsal horn neuron respon se activated by visceral noxious afferent and this action needs the participation of the center above the spinal cord.